Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help 
CURLOPT_HEADERDATA(3)	    Library Functions Manual	   CURLOPT_HEADERDATA(3)

NAME
     CURLOPT_HEADERDATA - pointer to pass to header callback

SYNOPSIS
     #include <curl/curl.h>

     CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HEADERDATA, void *pointer);

DESCRIPTION
     Pass a pointer to be used to write the header part of the received data to.

     If  CURLOPT_WRITEFUNCTION(3)  or CURLOPT_HEADERFUNCTION(3) is used, pointer
     is passed in to the respective callback.

     If neither of those options are set, pointer must be a valid FILE * and  it
     is used by a plain fwrite() to write headers to.

     If  you  are  using libcurl as a Windows DLL, you must use a CURLOPT_WRITE-
     FUNCTION(3) or CURLOPT_HEADERFUNCTION(3) if you  set  this  option  or  you
     might experience crashes.

DEFAULT
     NULL

PROTOCOLS
     This functionality affects all supported protocols

EXAMPLE
     struct my_info {
       int shoesize;
       char *secret;
     };

     static size_t header_callback(char *buffer, size_t size,
				   size_t nitems, void *userdata)
     {
       struct my_info *i = userdata;
       printf("shoe size: %d\n", i->shoesize);
       /* now this callback can access the my_info struct */

       return nitems * size;
     }

     int main(void)
     {
       CURL *curl = curl_easy_init();
       if(curl) {
	 CURLcode result;
	 struct my_info my = { 10, "the cookies are in the cupboard" };
	 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

	 curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, header_callback);

	 /* pass in custom data to the callback */
	 curl_easy_setopt(curl, CURLOPT_HEADERDATA, &my);

	 result = curl_easy_perform(curl);

	 curl_easy_cleanup(curl);
       }
     }

AVAILABILITY
     Added in curl 7.10

RETURN VALUE
     curl_easy_setopt(3) returns a CURLcode indicating success or error.

     CURLE_OK (0) means everything was OK, non-zero means an error occurred, see
     libcurl-errors(3).

SEE ALSO
     CURLOPT_HEADERFUNCTION(3), CURLOPT_WRITEFUNCTION(3), curl_easy_header(3)

libcurl 			   2026-06-11		   CURLOPT_HEADERDATA(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=CURLOPT_HEADERDATA&sektion=3&manpath=FreeBSD+Ports+15.1.quarterly>

home | help